Merging r358547:

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r358547 | ruiu | 2019-04-16 19:12:47 -0700 (Tue, 16 Apr 2019) | 9 lines

Fix a crash bug caused by a nested call of parallelForEach.

parallelForEach is not reentrant. We use parallelForEach to call
each section's writeTo(), so calling the same function within writeTo()
is not safe.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41508

Differential Revision: https://reviews.llvm.org/D60757
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llvm-svn: 360791

Author: tstellar

lld/wasm/OutputSections.cpp

@@ -111,8 +111,8 @@ void CodeSection::writeTo(uint8_t *Buf) {
   memcpy(Buf, CodeSectionHeader.data(), CodeSectionHeader.size());
 
   // Write code section bodies
-  parallelForEach(Functions,
-                  [&](const InputChunk *Chunk) { Chunk->writeTo(Buf); });
+  for (const InputChunk *Chunk : Functions)
+    Chunk->writeTo(Buf);
 }
 
 uint32_t CodeSection::numRelocations() const {
@@ -176,15 +176,15 @@ void DataSection::writeTo(uint8_t *Buf) {
   // Write data section headers
   memcpy(Buf, DataSectionHeader.data(), DataSectionHeader.size());
 
-  parallelForEach(Segments, [&](const OutputSegment *Segment) {
+  for (const OutputSegment *Segment : Segments) {
     // Write data segment header
     uint8_t *SegStart = Buf + Segment->SectionOffset;
     memcpy(SegStart, Segment->Header.data(), Segment->Header.size());
 
     // Write segment data payload
     for (const InputChunk *Chunk : Segment->InputSegments)
       Chunk->writeTo(Buf);
-  });
+  }
 }
 
 uint32_t DataSection::numRelocations() const {
@@ -232,8 +232,8 @@ void CustomSection::writeTo(uint8_t *Buf) {
   Buf += NameData.size();
 
   // Write custom sections payload
-  parallelForEach(InputSections,
-                  [&](const InputSection *Section) { Section->writeTo(Buf); });
+  for (const InputSection *Section : InputSections)
+    Section->writeTo(Buf);
 }
 
 uint32_t CustomSection::numRelocations() const {